The present invention relates to circuit testers for electronic circuits, and more particularly, to a test socket for use in an electronic circuit tester.
A test socket provides a platform for mounting a packaged electronic circuit, such as an integrated circuit, in a test system. Packaged electronic circuits include packaged single-die electronic circuits and packaged multi-die electronic circuits. A package protects an electronic circuit from the environment and provides a set of pins for coupling the electronic circuit to a socket, such as a test socket.
In a test system, a test socket is typically mounted on a test substrate coupled to a control unit. The test substrate usually includes electronic interconnects, such as thin, narrow, conductive strips, for coupling electronic signals between the test socket and the control unit. The control unit includes a processor that communicates with a device under test (a packaged electronic circuit mounted on the test socket) by transmitting electronic signals to the packaged electronic circuit and receiving electronic signals from the packaged electronic circuit.
A test socket includes electrical connectors that have electrical characteristics, such as resistance, inductance, and capacitance. Preferably, the electrical characteristics of the electrical connectors included in a test socket are identical to the electrical characteristics of the electrical connectors included in a production socket. A production socket is a socket for mounting a packaged electronic circuit in the packaged electronic circuit""s intended operating environment. Unfortunately, the electrical characteristics of test socket electrical connectors are not always identical to the electrical characteristics of production socket electrical connectors. One reason for the differences is that test socket electrical connectors are designed to continue to operate after thousands of insertions while a production socket electrical connector is not typically designed to function for more than about one-hundred or fewer insertions. A test socket electrical connector designed for thousands of insertions usually has mechanical characteristics that differ from the mechanical characteristics of a production socket electrical connector designed for one-hundred insertions. These differences in mechanical characteristics lead to differences in electrical characteristics.
Testing a simple, low frequency electronic circuit on a tester having a test socket with electrical characteristics that differ from the electrical characteristics of the packaged circuit""s production socket does not usually cause false failures. A false failure is a failure which occurs during the test of an electronic circuit in a test environment, but which does not occur when the packaged electronic circuit is operating in the packaged electronic circuit""s intended operating environment.
However, testing a complex, high frequency electronic circuit on a tester having a test socket with electrical characteristics that differ from the electrical characteristics of the packaged circuit""s production socket can cause false failures. At high frequencies, different electrical characteristics in the electrical connectors can lead to significant differences between the amount of noise on the electrical connectors that couple power to the packaged electronic circuit being tested and the amount of noise on the electrical connectors that couple power to the packaged electronic circuit operating in its normal operating environment. These differences in noise can result in false failures in testing of the packaged electronic circuit.
For these an other reasons there is a need for the present invention.